Method of recording sound-vibrations.



P. W. FULLER. METHOD OF RECORDING $OUND VIBRATIONS.

APPLICATION FILED MAY 2, 1908.

Patented Sept. 21, 1909.

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UNITED sTAr srA T orruon.

PEBCY W." FULLER, OF BOST='ON, MASSACHUSETTS.

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tion with the accompanying drawing, is a specification, like numerals onthe drawing representing like parts.

This invention has for its object to provide a novel method of recordingmagnetically sound vibrations so that they may at any time thereafter bereroduced.

It is a fact that when a ody containing or coated with magnetiz' ablematerial is magnetized, the intensity of the magnetism at any point onthe body depends 011 the amount of magnetizable material at this point.I make use of this fact in practicing my improved method, which consistsbroadly in depositing on a wire, disk or other body, which is preferablyof non-magnetiza-ble material, a layer of magnetizable material whichvaries in thickness'at different points along the wire or disk inaccordance with the variations of the sound vibrations to be recorded,and then subsequently subjecting said wire or disk to the influence of amagnetic field strong enough to magnetize the magnetizable material tosaturation point.

Since said wire or disk has a layer of varying thickness of themagnetizable material thereon, the result of thus magnetizing it will bethat said wire or disk will have at different points along its lengthmagnetism of different strengths, (this being so because the magneticstrength at any point has a definite relation to the thickness of themagnetizable material on the body at this point,) and the completelymagnetized wire or disk will represent a magnetic sound record. IVhen asound record thus made is passed over the poles of atelegraphone-reproducing apparatus, the sound vibrations thus magnetically recorded on the wire or disk will be reproduced in a wellknown manner.

While it is possible to carry out my method in a great variety of ways,I have shown in the drawings more or less diagrammatically one simpleapparatus for accomplishing the desired result, it being understood,however,

that I have not gone into detail of the construction of such anapparatus.

,Figure 1 shows diagrammatically one apparatus for carrying out myimproved mania filed May 2,1908. Ser'ialNo.430,45 1. I

- Specification drums-mm; Patente l-bjept 21-,1909

method; Fig. 2' is a detail of a magnet'for material has been de ositedthereon; Fig. 3 are detail of the shield for protecting'the wire fromelectrolytic action except at the point Where the magnetizable materialis to be deposited; Fig. 4 is a section through the electro-platingapparatus on the line w-w, Fig. 1.

1n the drawings I have shown mymethod as it would be applied inrecordingsound vibrations on a wire, but I wish it understood that the methodherein dmcribed can be carried out in recording sound vibrations on aplate, disk, cylinder or other body. I deem it preferable to use a bodyof non-magnetizable material, though my invention is not limited to theuse of such a material.

For convenience sake I will hereinafter refer to the body on which thesound record is made as the wire, but I wish it distinctly understoodthat by using this term herein I do not limit myself to the use of awire for carrying out my method.

In carrying out my method in the preferred way, I pass the wire on whichthe record is to be made through an apparatus adapted to electro-platethe wire with magnetizable material, .such, for instance, as nickel, andI cause an amount of magnetizable material to be thus deposited on thewire at different points along its length which varies as the soundvibrations to be recorded vary.

In electro-plating an article, the amount of plating deposited thereonin a given time varies with the strength of the current used in theelectro-plating bath, and I use this principle in securing the desiredend by providing means whereby the strength of the current employedvaries in accordance with the sound vibrations to be recorded. When thisis done, the thickness of the coating deposited on the wire at differentpoints (which thickness depends upon the strength of the current passingthrough the bath while those particular points of the wire are alsopassing therethrough) will vary in accordance with the variations in thesound 1 magnetizing the wire afterthe magnetizable I vibrations to berecorded. While it is pos- I which is connected with the transmitterwhich receives the sound vibrations to be recorded. The osci-llograph isarranged to reflect a beam of light from a umform'source of light, suchas a Nernst lamp, onto a tone chart, photographic wedge, or other screenof varying transparency, and associated with said screen is a; seleniumcell adapted to receive the light transmitted through the screen. Theamount of light which is thus received by the selenium cell at anyinstant depends u on the position on the screen into which the am oflight isreflected, and this in turn depends upon the sound vibrations.The selenium cell is in the circuit of the electro-plating bath and theresistance of this circuit is therefore varied in accordance with thevariations of the resistance of the selenium cell and the latter in turnvaries in accordance with the amount of light thrown thereon by theoscillogra h. In this.

way an amount of magnet1zab e material may be deposited on the wirewhich varies in accordance with the variations in-the sound vibrations.

Referring now more particularly tothe drawings, 3 designates the wire onwhich the record is to be made. This wire is shown 'as passing through abath 4 of an electro-plat mg a paratus 5. The anode or anodes 6 of the eectro-plating apparatus are of some magnetizable materia ,such, forinstance, as nickel, and the wire 3 which is preferably ofnon-magnetizable material .of good electrlcal conductlvity, such, forinstance, as copper,

constitutes the cathode of the apparatus;

The wire 3 is shown as passing over a guide 7 roll 7 situated below theeleetro-plating apparatus and over another guide roll 8 above the'same,said wire passing up through the bottom of the vessel contaming the bath4. The wire'is drawn through the vessel by any suitable means (notshown), and as it 1passes throu h the bath 4 it willbecome eectroplateifi The current for the electrolating apparatus is generatedfrom suitab e batterms or other current-producing means 9 i which areconnected by a wire 10 with the anode 6. Said-batteries orcurrent-producing means are also connected by a wire 11 with the 'deroll 7 over which the wlre 3 passes so t at the complete circuit for theapparatus comprises the batteries 9, wire 10,

'- selenium ce 16 0 any. suitable or usual construction which ispreferably situated at the focal point of a condensing lens 17.-Associated with-this lens 17 is a screen 18, the transparency of whichvaries- )rogressivel from one point to nnother, sai( screen pre erablybeing least trans arent at the central portion thereof, but iaving thereatest transparency at the edges therco This screen is situated toreceive a beam ofli ht reflected from the mirror 19 of an osci logra 11200i any suitable construction. This osci lograph is showndiagrammatically only in Fig. 1, and it comprises the usual mirror 19carried by the wires 21 which extend between the poles of a magnet 22,said wires being shown as passing over knife-edge bearings 23.. Thewires 21 are in a loop forming part of a circuit 24.

25 designates a constant sourceof illumi-.

nation such as a Nernst lamp, and 260 is a condensing lens arranged to'focus the beam of li ht from the lamp 25 onto the mirror 19. Wheneverthe current in the circuit 24 varies the wires 21 and the mirror 19 willbe deflected more or less according to the variations in the current andsince the mirror is situated to receive the beam of light from the lamp25 and reflect said light onto the screen 1.8 any deflection of themirror will cause a displacement on the screen of the reflected beam oflight. The current in the circuit 24 is arranged to be varied inaccordance with variations in the sound vibrations of the sound to berecorded, and for this purpose the circuit 24 is connected with atelephone transmitter 29, this preferably being done through the primary27 and secondary 26 of a transformer,the secondary 26 of the transformerbeing in the circuit 24, and the primary 27 of the transformer being inthe telephone circuit 28 that includes the transmitter 29. Any soundvibrations received by the sound transmitter 29 will cause variations inthe current in the telephone circuit 28, and such variations operatethrough the transformer 26, '27 to cause corresponding variations in thecurrent in the circuit 24.

These variations in the circuit 24 cause a cor responding vibration ofthe mirror 19 and thus the reflected beam of light is displaced on thescreen 18, the displacement varying from one side to the other of thecenter in accordance with the sound vibrations received by thetransmitter. The light which is transmitted through the screen 18 is received by the condensing lens 17 and focused onto the selenium-cell l6and the arrangemetal deposited on the wire 3 as thelatter is eeaeoedrawn throu h the bath 4: will vary in accordance wit the variations inthe sound vibrations received by the transmitter 29. After the wire 3has been drawn through the bath 4, therefore, it will have on it acoating of nickel or other magnetizable material the thickness of whichat difi'erent points along the wire varies in accordance with thevariations in sound vibrations received by the transmitter 29. v

After the wire has been drawn through the electro-platin apparatus it ismagnetized by a magnet'c field of suiiicient strength to magnetize thecoating of magnetizable material to saturation. This may be doneconveniently by passing it betweem the oles 30 and 31 of a magnet 32having a uni 'orm magnetic field. The extent to which the wire ismagnetized at any point is determined by the amount of magnetizablemate-' rial on the wire at this point and therefore when the wire hasbeen completely magnetized it will have extended along its lengthamounts of magnetism which vary in accordance with the variations in thethickness of the magnetizable material, or, in other words, it will havealong its len th magnetism which varies in intensity at different pointsin accordance with variations in the sound vibrations received by thetransmitter. In this way a magnetic sound record is produced which canbe used in an ordinary telegraphone-reproducing apparatus for thepurpose of reproducing the sounds received by the transmitter.

My method is adapted for making simultaneously a plurality of records ofthe same sound vibrations, for it is perfectly feasible to pass throughthe electro-plating apparatus a plurality of wires simultaneously,

' and if this is done, each wire will receive a similar coating ofmagnetizable material which varies in thickness in accordance with thevariations in sound vibrations. To do this merely requires the placingin the bath of a plurality of the protecting tubes 12 and 13, as shownin Fig. 4, and running a wire through each one of these tubes. All ofthese wires could then be simultaneously magnetized by means of a magnethaving the shape shown in Fig. 2 wherein the poles 30, 31 are of asuflicient length to permit a plurality of wires 3 to pass between themsimultaneously.

It is not essential to my invention that the oscillograph method beemployed for securing variations in the current throu h theelectro-plating apparatus correspond mg to variations in the soundvibrations to be recorded, for since I believe I am'the first to provideany means for varying the amount of magnetizable material deposited onthe wire by the variations in sound vibrations to be recorded, I desireto claim this feature broadly regardless of the apparatus em-- ployedfor converting the energy of the sound vibrations into varyingelectrical energy adapted to vary the amount of material dcposited onthe wire. The oscillograph method, however, constitutes a convenient wayof securing this end. Nelther 1s it essential to my invention that thebody on which the sound record is made should be in the form of a wire,although a wire has advantages over a disl-nplate or other shaped bodyin the ease with which it may be manipulated and in the length of therecord which may be readily placed thereon.

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent is V 1. The step in the method of producingsound records which consists in' depositing ona body a layer ofnon-magnetized magnetizable material which varies in thickness atdifferent points in accordance with the variations in the soundvibrations to be recorded.

2. The method of producing sound records which consists in depositing ona body a layer of magnetizable material which varies in thickness atdifferent points in accordance with the variations in the soundvibrations to be recorded and then subjecting said body to a uniformmagnetic influence to form a permanent magnetic record.

3. The steps in the method of producing a sound record which consist indepositing a layer of non-magnetized magnetizable material on a body andcausing said layer ,.to have a thickness which varies at differentpoints on the body in accordance with the variations of the soundvibrations to be recorded.

4;. The method of producing a sound record which consists in depositinga layer of magnetizable material on a body and causing said layer tohave a thickness which varies at different points on the body inaccordance with the variations of the sound vibrations to be recordedand then magnetizing said layer by means of a uniform magnetic fieldthereby to form a permanent magnetic record.

5. The steps in the process of producing a sound record which consist inpassing a body through an electro-plating apparatus adapted to depositthereon a layer of magnetizable material and causing the current throughthe apparatus to vary in accordance with the variations in the soundvibrations to be recorded.

6. The method of producing a sound record which consists in passing abody through an electro-plating apparatus adapted to deposit thereon alayer of magnetizable material and causing the current through theapparatus to vary in accordance with the variations in the soundvibrations to be recorded and then magnetizing said layer by vertin thesound vibrations to be recorded into elec trical ener y and causing saidelectrical energy to eposit a layer of magnetizable material on a bodyand then m'a netizing said body by subjecting it to the in uence of auniform magnetic field thereby to' form a permanent magnetic record.

91 The method of producing sound records which consists in depositing ona non-magnetizable body a layer of magnetizable material which varies inthickness at diflerent points on the body in accordance with thevariations in the sound vibrations to be recorded and then subjectingsaid body to the influence of a uniform magnetic field to form amagnetic record.

10. The step in the method of producing magnetic sound records whichconsists in passing a body through a liquid electrolyte I and decom osmgmore or less of the electrolyte according to the variations in the soundvibrations to be recorded.

11.' The step in the method of producing sound records which consists inpassing a body through a liquid electrolyte and passa current throughsaid electrolyte which varies in accordance with tions to be record-d.-

12. The method of producing magnetic sound records which consists inpassing a body through a liquid electrolyte, causing an electric currentto pass through said electrolyte which current varies in accordance withthe sound vibrations to be recorded whereby a layer of varying thicknessis depositedon said body and thensubjectin'g said body to a uniformmagnetic influence.

J 13. The method of producin sound ords whichconsists in passing a 0d ofnon ma etizable material through an e ectrolyte an simultaneouslypassing a current through said electrolyte which varies in' accordancewith the sound vibrations to be recorded and subsequentlysubjecting saidbody to a uniform magnetic influence.

. 14. The process of making sound records which consists in depositingon in body a layer of magnetizable material which varies in thickness atdifferent points of the body in accordance with the variations in thesound vibrations to be recorded and then magnetizing said layer tosaturation point.

In testimony whereof, I have signed my name to this specification in thepresence of two subscribing witnesses. I

' PERCY W. FULLER.

Witnesses:

BERTHA F. I-lnUsnR, THOMAS J DRUMMOND.

the sound vibra-

